1. Field of the Invention
The present invention relates generally to liquid thermal management systems for thermally managing electronic devices and more specifically it relates to a spray chamber valve control system for ensuring that coolant is sufficiently available at the intakes of pumps in a spray cooled environment regardless of the attitude, acceleration or deceleration of a spray chamber.
2. Description of the Related Art
Thermal management systems for electronic systems utilized in various environments have been in use for years. In order to maintain maximum performance from electronic components, the components need to be maintained within a relatively narrow temperature band. Thermal management systems are utilized to maintain this desired narrow temperature band.
In addition, some external environments include hostile elements such as but not limited to dust, sand, debris, salt, water, fog, condensed water vapor, contaminants and the like, which require the complete isolation of electronic components from the harsh external environment. Extreme external environments are encountered within various applications such as aircraft, ships, ground based applications and the like. It is absolutely crucial that electronic components be maintained in a safe internally controlled environment when in extreme external environments.
Conventional thermal management systems commonly utilized today are comprised of air-cooled enclosures (forced flow or free flow), conduction cooling and liquid immersion cooling. The main problem with air-cooled enclosures is that they introduce harmful external elements into the electronics enclosure. Another problem with air-cooled enclosures is that they do not provide a method to increase the temperature of electronic components to a desired operating temperature when the external temperature is extremely low (e.g. −65° C.). Problems with conduction cooling systems include increased weight, increased size, increased mass, expensive, reduced shock and vibration tolerance, and reduced electronic component performance. A significant design limitation with conduction cooling systems is that they must be in direct contact with the electronic components which limits flexibility and increases expense. The large mass also increases the amount of time required to increase the temperature of electronic components to a desired operating temperature.
Spray cooling technologies are being adopted today as the most efficient option for thermally managing electronic systems in an enclosed internal environment. Spray cooling preferably utilizes an atomized dielectric spray that is applied directly to the electronic devices within a sealed spray chassis thereby forming a thin film on the electronic devices. Spray cooling may be performed locally (i.e. where the chip is sprayed directly) or globally (i.e. where the chip and surrounding electronics/boards are also sprayed).
U.S. Pat. No. 5,220,804 entitled High Heat Flux Evaporative Spray Cooling to Tilton et al. describes an early chip spray cool system that achieves high heat flux cooling by optimizing droplet momentum, momentum of the thin coolant film, and by managing vapor and excess fluid in the system. U.S. Pat. No. 6,108,201 entitled Fluid Control Apparatus and Method for Spray Cooling to Tilton et al. describes the usage of global spray cooling technology to cool a printed circuit board.
While these devices may be suitable for the particular purpose to which they address, they are not as suitable for ensuring that coolant is sufficiently available at the intakes of pumps in a global spray cooled environment regardless of the attitude, acceleration or deceleration of a spray chamber. Conventional spray cooling applications do not provide adequate assurance of ample liquid coolant to the intake of the pumps.
In these respects, the spray chamber valve control system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of ensuring that coolant is sufficiently available at the intakes of pumps in a spray cooled environment regardless of the attitude, deceleration and/or acceleration of a spray chamber.